iio: buffer: Make IIO DMA fence release RCU-safe

The `dma_fence` documentation states that if a custom release
implementation is provided, the `dma_fence` object must be freed in an
RCU-safe way. The current `iio_dma_fence` implementation uses `kfree()`,
which might result in a use-after-free.

Remove the custom `release` implementation. This makes the DMA fence core
fall back to `dma_fence_free()`, which calls `kfree_rcu()` on the fence.
This requires that the fence be the first member of `struct iio_dma_fence`.

Using the default release method for extended DMA fence structures is a
common pattern.

Reported-by: codex:gpt-5.6
Fixes: 3e26d9f08fbe ("iio: core: Add new DMABUF interface infrastructure")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions